Wet clutch

ABSTRACT

A wet clutch ( 1 ) with at least one friction disk ( 8 ) that can be clamped by an axially displaceable piston ( 5 ) against an end disk ( 7 ). In order to provide a cost-effective and more silent design, the end disk is permanently attached at the housing. Several variants are proposed for the attachment of the end disk.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is filed under 35 U.S.C. §120 and §365(c) as acontinuation of International Patent Application No. PCT/DE2009/001531filed Oc. 29, 2009 which application claims priority from Germany PatentApplication No. 10 2008 056 640.3 filed on Nov. 10, 2008 whichapplications are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to a wet clutch with at least one friction discthat is loadable by a piston relative to an end disc.

BACKGROUND OF THE INVENTION

Wet clutches are known e.g. from DE 10 2007 053 974 A1 as converterlockup clutches for hydrodynamic torque converters, as separate wetclutches, as startup clutches or as twin clutches for twin clutchtransmissions. Thus plural friction discs associated with an input sideand an output side of the wet clutch are stacked in an alternatingmanner to form a disc packet and are received torque-proof and axiallymoveable with limits on two radially offset disc supports as a functionof their input side or output side association. Thus, an end disc isarranged on a disc support. An axial travel of the end disc is limitedat a stop of the disc support. The disc packet is pressed or clampedagainst the end disc by an axially moveable pressure loadable piston fortorque transfer through the wet clutch. By receiving the end disc on thedisc support and axially supporting it at this location a particularconfiguration can cause noise, in particular when there is no load or ina load range of the drive unit with small to medium torque. Furthermorethe deformation properties of the end disc that is not fixated axiallycan cause undesirable disadvantages on the load. Eventually the cost foran inner and an outer disc carrier is comparatively high.

BRIEF SUMMARY OF THE INVENTION

Thus, it is the object of the invention to provide a wet clutch which iscost-effective, low noise and suitable for transferring high torque.

The object is achieved through a wet clutch with a housing driven by adrive unit and with at least one friction disc that is configured to beclamped against an end disc through a piston that is axially moveablethrough a pressure. The end disc is axially and radially fixed andreceived torque-proof at a housing. Through this attachment of the enddisc at the housing a radially outer disc support can be omitted.Additionally, higher torques can be transferred through the diameter,thus achievable with the same number of friction discs due to the largerfriction diameter of the friction discs. A smaller number of frictiondiscs can be used for the same transferable torque. Where necessary theinput side friction discs can also be engaged at accordingly providedcircumferential profiles like inner teethings of the housing. Throughomitting the outer disc support lower noise configurations can beproposed since e.g. the interior of the wet clutch can be configured ina more homogenous manner.

Thus, it has proven particularly advantageous when the end disc is notwelded, but received through form locking or friction locking Thus, theattachment of the end disc with the respect to the movement degrees offreedom of the non-connected end disc relative to the housing can beprovided through different attachment methods. In particular, formovement degrees of freedom in axial direction and in circumferentialdirection the same or different friction locking or form locking methodscan be used.

For example, a torque transfer of the end disc, thus an attachment ofthe end disc in circumferential direction relative to the housing, canbe provided through friction locking in that the end disc is radiallyclamped relative to the housing in that the end disc is pressed into theinner circumference of the housing or attached forming a plasticdeformation of the housing and/or the end disc. Alternatively, formlocking can be provided between the end disc and the housing in that theend disc is radially or axially cut into the housing. Furthermore,profiles that are complementary to one another like material recesses,recesses or threads like fine threads, standard threads or trapezoidthreads can be provided.

The axial fixation of the end disc can be provided e.g. in case offriction locking through impressing or forming a plastic connection orin case of form locking through a plastic connection. Furthermore, whenforming the housing from two housing shells, one housing shell, e.g. thepump of a torque converter, can be used as an axial stop for thefriction disc.

In order to provide a plastic deformation between the end disc and thehousing the end disc, the housing, e.g. one of the two housing shells,or both housing shells can be deformed plastically.

In order to configure the connection furthermore, the end disc and thehousing can be caulked together. Alternatively, the housing can beroller-burnished about the end disc. The end disc can be permanentlyinserted into the housing through a wobbling process. The housing can bedeformed through forging or embossing, so that the end disc can bepermanently received in the housing. In another advantageouslyconfigured embodiment, an end disc can be provided that is rivetedtogether with the housing. In particular, for cost reasons and formaintaining tightness of the housing, seal buds can protrude from thehousing at which the end disc is riveted together with the housing.

A plastic deformation for attaching the end disc at the housing can thusbe provided completely over the entire circumference and/or in sectionsby providing circular segments that are distributed over thecircumference. A plastic deformation is provided at the circularsegments. For example the end disc can be received through frictionlocking like e.g. through roller-burnishing over the entirecircumference for torque-proof reception and can be caulked along thecircumference in segments or partially for axial attachment to thehousing.

The end disc can have a planar, conical or dish shape. Thus, thedish-shaped end disc can be partially applied to the housing. Inparticular for stabilizing the end disc beads, embossings and/or ribscan be provided thereon. Furthermore, the end disc can include at leastone material recess at least at one of its circumferences or radiallythere between. Material recesses of this type can be provided throughholes, punching, teething and/or notching and can be used for betterflow through of pressure medium for controlling the piston and/orcooling the friction discs, in particular their liners.

Furthermore it has proven advantageous to vary the material thickness ofthe friction disc. Thus in particular material thicknesses can beadvantageous that vary over the radius of the end disc. Thus e.g. ahigher stiffness can be achieved for minimum material use.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The nature and mode of operation of the present invention will now bemore fully described in the following detailed description of theinvention taken with the accompanying drawing figures, in which:

FIG. 1 illustrates a wet clutch with an end disc with an axial stop andplastically generated friction locking in rotation direction;

FIG. 2 illustrates a wet clutch with an end disc with an axial stop andteething in rotation direction;

FIG. 3 illustrates a wet clutch with an end disc provided with holes;

FIG. 4 illustrates a wet clutch with a riveted end disc;

FIG. 5 illustrates a wet clutch with a notched end disc;

FIG. 6 illustrates a wet clutch with a caulked end disc; and

FIG. 7 illustrates a wet clutch with an end disc that is caulked in analternative manner compared to the embodiment of the wet clutch of FIG.6.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates the upper half of the wet clutch 1 arranged about therotation axis 2. The wet clutch 1 is formed from an input component 3and an output component 4. The input component 3 includes the piston 5connected torque-proof with the housing 6 that is moveable within limitsrelative to the housing. The input component 3 includes the end disc 7permanently received at the housing. The output component 4 forms thefriction disc 8 that is clampable between the piston 5 and the end disc7. The friction disc is connected torque-proof through the innerteething 9 with the input component 12 of the torsion vibration damper11 through an outer teething 10 embossed in the input component 12.

The end disc 7 is received at the housing 6 in an axially fixated andtorque-proof manner. Thus, the end disc is configured dish-shaped andaxially fixed on one side through a radially inner radially extendingportion 13 at a radially extended portion 15 with shoulders of thehousing shell 14 of the housing 6. In the other direction the end disc 7is axially fixed at a stop 16 of the housing shell 17 that is radiallyreduced relative to the inner diameter of the housing shell 14. The twohousing shells 14, 15 are welded together during final assembly and formthe housing 6 of the wet clutch 1, wherein the housing shell 17 cansimultaneously form the pump of the torque converter when using the wetclutch 1 as a converter lockup clutch.

After installing the piston 5 and the friction disc 8 the end disc 7 isinserted torque-proof through a plastic deformation 18 of the innersurface of the housing shell 14 of the housing 6. Thus, a fine profile19 can be fabricated at the inner surface of the housing shell 14. Thefine profile has a smaller inner diameter than the outer diameter of theend disc 7. When axially inserting the end disc 7 at the stop of theportion 15, the fine profile 19 of the housing shell 14 is plasticallydeformed and a frictional engagement is formed, so that the end disc 7is rotationally fixated and after completing the remaining innerportions of the housing 6 the housing shell 17 is axially fixated at thehousing 6 through the stop 16.

FIG. 2 illustrates an embodiment of a similar wet clutch 1A that is analternative to the wet clutch 1 of FIG. 1. Differently from the wetclutch FIG. 1 the end disc 7A is received in a form locking manner atthe housing 6. Thus, the outer circumference of the end disc 7A includesan axial teething 20 which is in engagement with a face teething 21 ofthe housing shell 17. Thus, the face teething 21 simultaneously formsthe stop for the end disc 7 a in the direction of the torsion vibrationdamper 11. In a direction of the piston 5 the radial portion 15 of thehousing shell 14 forms an axial stop for the radially inner portion 13of the dish shaped end disc 7 a. The end disc 7 a is thus inserted intothe housing shell 14 and centered at the inner circumference of thehousing shell 14. The form locking to the housing shell 14 is thusconfigured when joining the two housing shells 14, 17.

FIG. 3 illustrates a wet clutch lb that is similar to the wet clutch 1of FIG. 1 with the difference that the end disc 7 b includes at least arecess 22 like e.g. a punched out recess. Besides mass savings at theend disc 7 b the recesses 22 facilitate an improved exchange of pressuremedium for cooling the friction liners 23 of the friction disc 8. Thus,a separation into the pressure chambers 25, 26 is provided foraccordingly configured wet clutches or in a three channel torqueconverter, wherein the separation takes over the cooling and theactivation of the wet clutch 1 b (also of the remaining illustrated wetclutches). For closing the wet clutch 1 b the pressure chamber 26 isloaded with a pressure medium with higher pressure than the pressureapplied to the pressure chamber 25. Thus the piston 5 moves axially andloads the friction disc 8 against the end disc 7B so that a frictionalengagement is formed between the two components and torque istransferred to the torsion vibration damper 11. Additionally thepressure of the pressure cavity 24 is increased over the pressure of thepressure cavity 25 and a pressure medium flow is provided over therecess 22 and the friction liners 23 wherein the pressure medium flowcools the friction liners 23.

FIG. 4 illustrates an embodiment of a wet clutch 1 c in which the enddisc 7 c is riveted radially outside the friction disc 8 at the radiallyaligned portion 15 of the housing shell 14 of the housing 6 and is thusattached torque proof or axially fixed and in a centered manner at thehousing 6. In the illustrated embodiment, the rivets 27 are formed fromrivet buds which are pressed out of the housing shell 14. In thefollowing the only partially illustrated input component 12 of thenon-illustrated torsion vibration damper and the disc support 28 withthe outer teething for torque proof connection of the friction disc 8are configured in two portions.

FIG. 5 illustrates the wet clutch ld in which the end disc 7 d in thehousing 6 is fixed through material displacement of the end disc 7 d inan axially fixated and torque-proof manner. An axial stop 29 is thusconfigured in the housing 6 for axially contacting the end disc 7 d. Acircumferential groove 30 can be provided at the housing 6 into whichmaterial of the end disc 7 d in the form of an annular protrusion 31 isdisplaced into the annular groove 30 through axial force loading throughone or plural rollers distributed over the circumference or through apressure loaded chisel. Differently from the end discs 7, 7 a, 7 b ofFIGS. 1 through 3 the end disc 7 d is configured planar in theillustrated embodiment.

FIGS. 6 and 7 illustrate wet clutches le and if in which the end discs 7e, 7 f that are configured planar are respectively caulked with thehousing 6 in axial direction. The end discs 7 e, 7 f thus include anouter profile like an outer teething 32, 32 a which forms a form lockingengagement with an inner profile that is provided in a complementarymanner in the inner circumference of the housing 6 so that the end disc7 e, 7 f is received torque-proof in the housing 6. After applying theend disc 7 e, 7 f at the stop 29 of the housing 6 the end disc 7 e, 7 fis caulked with the housing 6 for axial safety. Thus, caulking lugs 33are formed through radially displacing material of the housing 6 in thewet clutch le of FIG. 6. The caulking lugs are distributed over thecircumference. The caulking lugs 33 a are formed in the wet clutch if ofFIG. 7 through an axial displacement of material of the housing 6. Asevident e.g. from the view of the end disc 7F of FIG. 7, the outerteething 32 a of the end discs can include relief openings 34 throughwhich pressure medium balancing can be provided between the pressurecavities 24, 25 for cooling the friction disc 8. In order to increasethe torque that is transferrable through the connection of the end disc7 f and the housing 6, the material displacements of the housing 6 canat least partially reach over the relief openings 34.

REFERENCE NUMERALS AND DESIGNATIONS

1 Wet clutch

1 a Wet clutch

1 b Wet clutch

1 c Wet clutch

1 d Wet clutch

1 e Wet clutch

1 f Wet clutch

2 Rotation axis

3 Input component

4 Output component

5 Piston

6 Housing

7 End disc

7 a End disc

7 b End disc

7 c End disc

7 d End disc

7 e End disc

7 f End disc

8 Friction liner

9 Inner teething

10 Outer teething

11 Torsion vibration damper

12 Input component

13 Portion

14 Housing shell

15 Portion

16 Stop

17 Housing shell

18 Plastic deformation

19 Fine profile

20 Axial teething

21 Face teething

22 Recess

23 Friction liner

24 Pressure cavity

25 Pressure cavity

26 Pressure cavity

27 Rivet

28 Disc support

29 Stop

30 Circumferential groove

31 lug

32 Outer teething

32 a Outer teething

33 Caulking lug

33 a Caulking lug

34 Relief opening

1. A wet clutch comprising a housing (6) driven by a drive unit and atleast one friction liner (8) configured to be clamped against an enddisc (7, 7 a, 7 b, 7 c, 7 d, 7 e, 7 f) through a piston (5) that isaxially movable through pressure, wherein the end disc (7, 7 a, 7 b, 7c, 7 d, 7 e, 7 f) is supported in an axially, radially and rotationallyfixated manner at the housing (6).
 2. The wet clutch according to claim1, wherein the end disc (7, 7 a, 7 b, 7 c, 7 d, 7 e, 7 f) iscircumferentially supported through friction locking or form locking atthe housing (6).
 3. The wet clutch according to claim 1, wherein the enddisc (7, 7 a, 7 b, 7 c, 7 d, 7 e, 7 f) is axially supported throughfriction- or form locking at the housing (6).
 4. The wet clutchaccording to claim 1, wherein the end disc (7, 7 a, 7 b, 7 c, 7 d, 7 e,7 f) is permanently connected with the housing through impressing orthrough a plastic deformation.
 5. The wet clutch according to claim 1,wherein the end disc (7, 7 a, 7 b, 7 c, 7 e, 7 f) is axially fixated ata stop (16, 29) formed by at least one of two housing shells (14, 17) ofthe housing (6).
 6. The wet clutch according to claim 1, wherein the enddisc (7 e, 7 f) is caulked with the housing (6).
 7. The wet clutchaccording to claim 1, wherein the housing (6) is roller-burnishedrelative to the end disc (7 d).
 8. The wet clutch according to claim 1,wherein the end disc (7 c) is riveted together with the housing (6). 9.The wet clutch according to claim 1, wherein the end disc is attached atthe housing through a wobble process.
 10. The wet clutch according toclaim 1, wherein the end disc is supported at the housing through aforging- or embossing process.
 11. The wet clutch according to claim 1,wherein the end disc (7, 7 a, 7 b, 7 d) is received over its entirecircumference at the housing (6).
 12. The wet clutch according to claim1, wherein the end disc (7 e, 7 f) is supported relative to the housing(6) in circumferential segments at least with respect to one degree offreedom of motion freedom.
 13. The wet clutch according to claim 1,wherein the end disc (7, 7 a, 7 b, 7 c, 7 d, 7 e, 7 f) has a planar,conical or dish shape.
 14. The wet clutch according to claim 1, whereinend disc includes beads, embossings, and/or ribs.
 15. The wet clutchaccording to claim 1, wherein the end disc (7 b, 7 e, 7 f) includes atleast one recess (22) or relief opening (34) at least at onecircumference of the end disc or radially between circumferences of theend disc.
 16. The wet clutch according to claim 1, wherein a materialthickness varies over the circumference or in radial direction.